This project's overall goals are: 1) to investigate the impact of language barriers on medication adherence (following a prescribed medication program) and treatment intensification (increasing treatment) in patients with diabetes mellitus (DM), hypertension (HTN), and hyperlipidemia (HL); and 2) to identify modifiable factors for targeting future interventions to enhance outcomes. Approximately 55 million people in the United States report speaking a foreign language at home and nearly 45% of these individuals (~25 million) report limited English proficiency (LEP). Patients with LEP are at increased risk for poor health care quality and poor health outcomes, but little research has looked at how language barriers affect treatment of common chronic conditions. The proposed project will be conducted at Group Health, a large, non-profit integrated health system in the Pacific Northwest with a long history of innovative health services research. A novel conceptual model of adherence to prescribed medications in LEP patients, based on previously developed adherence models, was created and used to guide selection of key factors to analyze. Data for the study will be collected from Group Health's extensive electronic health systems, augmented by surveys in Chinese, Korean, Spanish, Vietnamese, and English, given to 600 LEP patients. Data will be analyzed using advanced statistical methods. The Specific Aims of the project are: Aim 1) To evaluate how medication adherence, and treatment intensification, differ by LEP status in patients with DM, HTN, and HL; Aim 2) To characterize differences between patients by LEP status in patient, provider, and health system factors associated with medication adherence and treatment intensification, and to investigate the extent to which these factors explain differences identified in Aim 1 between LEP and non-LEP patients; and Aim 3) To identify modifiable patient, provider, and health system factors associated with medication adherence and treatment intensification in LEP populations. Findings from this project will go well beyond previous studies on LEP patients by identifying theory-driven modifiable patient-, provider- and system-levels factors associated with medication adherence and treatment intensification in subjects with limited English skills. The project brings together junior and senor researchers from Group Health, the University of Washington, UCLA, and the University of Wisconsin-Madison. We expect our findings to stimulate research on improving care for LEP patients, through publications in peer-reviewed journals and new grant applications that propose interventions to improve medication adherence and treatment intensification in patients facing language barriers. PUBLIC HEALTH RELEVANCE: Approximately 55 million people in the United States report speaking a foreign language at home and 45% of these individuals (~25 million) report limited English proficiency (LEP). This project's goals are to investigate the impact of language barriers on medication adherence and treatment intensification in patients with diabetes mellitus (DM), hypertension (HTN), and hyperlipidemia (HL), and to identify modifiable factors for targeting future interventions to enhance outcomes. Findings from this study will increase understanding of how language barriers contribute to disparities in health and provide groundwork for future research and interventions to reduce disparities due to language barriers.